1. Field of the Invention
This invention relates to apparatus for clamping a fitting to a pipe such as during an electrofusion process, and more particularly to a clamping apparatus which is installed from only one side of the pipe and does not require support on the opposite side thereof.
2. Description of the Prior Art
Plastic pipe and fittings are now widely used in a great variety of applications. Such fittings and pipe are frequently connected using adhesives. However, adhesives may not seal completely if not carefully applied, and in some cases, the adhesives themselves may be hazardous.
A recent development is the use of electrofusion fittings. Such fittings comprise a body of thermoplastic material having an electrical resistance heating or fusing element molded into the fitting adjacent to a surface of the body. In operation, an electric current is supplied to the electrofusion element which causes it to heat so that the thermoplastic material in the pipe is melted or softened and thereby the fitting is fused or welded to the pipe or another fitting. Electrofusion has the advantages of eliminating adhesives and providing a satisfactory, consistent connection between the plastic components. This reduces the likelihood of bad connections and the resultant leakage.
One known fusing procedure is to attach a saddle joint to a length of pipe. The saddle joint can comprise one or more connections so that another line may be connected and tapped into the original pipe. Also, other elements, such as valves, etc., may be connected to the pipe in this way.
In attaching a fusion saddle joint, a known clamping apparatus is typically positioned around the pipe. This clamping apparatus has a mechanism for clamping the fitting to one side of the pipe and clamping against the opposite side of the pipe so that the fitting is held in place during the fusion process. That is, such prior art clamping devices require support of the pipe on the opposite side from the saddle fitting to be attached.
Such a clamping apparatus have worked well, but in some applications, it is not convenient to use because it requires support on the opposite side of the pipe. For example, the location of the pipe may prevent the positioning of a support thereunder. Also, in the case of buried pipe, to use such clamping apparatus, it is necessary to totally excavate around the pipe so that the apparatus can be positioned under the pipe.
Therefore, there is a need for an apparatus which does not require a support on the opposite side of the pipe and which can be installed from only one side of the pipe. The clamping apparatus of the present invention meets this need and can be installed from one side of the pipe. It clamps the fitting and an inner surface of the pipe, thus being usable in situations where a support under the pipe is not practicable or would add additional costs, such as where a pipe portion is buried.